As it is known, sunlight can seriously damage the skin.
Mainly the persons of clear skin and difficult browning are those most susceptible to damage deriving from an excessive exposure to the sun.
The ravaging effects, caused by an excessive radiation, are evident if one compares the conditions of the skin continuously exposed, for a long time, to the sun, such as for example the skin of the farmers, with the skin of persons having the same genetic characteristics, but not subjected to a continuous exposure.
Actually, in the case of a continuous exposure to the sun, and as the years pass, atrophy, deep wrinkles, telangiectasis, dryness of the skin and anomalous pigmentation occur.
The cutaneous ageing, even if it is not overcome, is much less evident and does not assume the gravity and intensity of the damage occurring in a person continuously exposed to the sun without any suitable protection.
The most evident signs of a premature and great cutaneous ageing can be detected just in those regions of the skin which are not usually protected by cloths, such as the face, neck, arms, hands and legs.
It is symptomatic, but explicative, the fact that a person thirty years old exposed during the day to the sun rays presents, in the not protected skin regions, the same damage of a person of fifty/sixty years.
On the contrary, that same person thirty years old, if remains in a closed environment, as it occurs in northern countries with northern climates, will have a skin like that of a twenty year old person.
The aggression to the skin due to the sunlight has been identified and acknowledged in the UV component, in particular at the wave length from 290 to 320 nanometers.
Also that portion of the UV rays from 320 to 400 nanometers causes to so-called actinic insults.
Moreover, the infrared rays, also called thermal rays since they transmit heat to the skin and exceed 700 nanometers, can overburden, together with the UV rays, the cutaneous damage occurring under a full sun exposure condition.
Actually, since the browning or tanning, or, better, melanin from which said browning derives, defends and protects the skin from the UV ray impact, an already tanned person should proceed with caution in taking the sun rays.
However, when the tanning is lacking, then sunlight must be taken, little by little, with a very great care and screening or shielding the skin by suitable and well calibrated solar filters is necessary.
In particular, it is absolutely necessary not to alternate sun periods with consequent tanning and no-sun periods with a tanning loss.
In fact, in this manner, the skin, not protected by melanin, would be exposed to continuous insults by UV rays.
This apparent paradox could bring a person to state that it would be better to take the sun continuously with the skin in a tanned condition instead of taking it alternatively "hiccup-wise".
Accordingly, it would be necessary to filter the sun rays in order to eliminate an excess of UV rays.
On the other hand, if a good tanning is desired, it is necessary that a portion of the UV rays reaches the skin in order to burst forth the formation of the required pigment.
However, with respect to the quality and amount of solar filters, it is practically not possible to adjust in a manner suitble for all types of skins requirements because of different delicacy, different doses and functionalities.
Because of the mentioned reason, and in order to prevent the skin from being seriously damaged, active agents or associations thereof should be used which, in addition to reducing the impact of the UV rays would be susceptible to preventing and repairing the negative effects of that part of radiation which, anyhow, must pass through the skin.
Accordingly, it will be necessary to use substances preventing the formation of and combating redness, inflammations and erythemas, which are due to free radicals, to a peroxidation as well as to the generation of substances which are damaging to the cells and tissues.
It is known that the skin is the most complex and extended organ of a human organism. Even if the human organism includes organs which are more important from a mere life standpoint, such as heart, brain, kidneys, lungs and so on, without which the life would be impossible, also the skin must be considered as essential for life. In this connection it is sufficient to think that a human organism cannot survive if a comparatively high amount of its skin surface is removed therefrom.
Those persons who do not expose themselves to the sun have a smooth skin, without stains up to ninety years, and present relaxation and only a deepening of the expression wrinkles.
On the contrary, those skins which have been excessively exposed to the insults of the sun will present dryness, deeper wrinkles, diffused naevus, an alternated color, couperoses, grooves, fissures, recesses and swellings. Moreover they have a hard rough and coriaceous undertouch.
All the above mentioned anomalous signs are indicative of great alterations and damage to the derma.
Actually, the skin is not only an organ for holding the other components of a body and for separating or defending them from the encompassing environment, but it is also the place of exchanges with the outer environment and for the synthesis of biochemical substances which, in addition to adjusting, coordinating and harmonizing their life, have an important meaning for the functionality and vital equilibrium of the overall organism.
Many histological variations have been disclosed because of the ageing of the skin under the effect of the sun rays and other causes damaging the skin.
At this time, it is necessary to distinguish the intrinsic causes which bring to the normal senescence from the extrinsic causes, in particular the sunlight, which bring to a premature much stronger cutaneous ageing.
The damages and faults caused by the UV rays can remain in a latent condition for tens of years but, at about fifty, as the defense mechanisms decrease and the normal regenerative processes lose efficiency, this damage becomes very evident.
In this connection it should be apparent that in addition to the aesthetic damage, degeneration and alteration of the cutaneous structure and functionality will also occur which cannot be recovered.
The premature ageing of the skin due to the sunrays will cause an alteration of the following structural, functional and biochemical parameters:
deep wrinkles; PA1 an alteration of the color; PA1 the appearance of sub-cutaneous small veins; PA1 a modification of the thickness; PA1 a dryness and roughness with a loss of the mechanical properties; PA1 a loss of resiliency, with a degradation of the resilient fibers; PA1 an alteration of the cell recovery and proliferation; PA1 modification of the penetrability of the sebum secretion and circulation; PA1 a degradation of the collagen and proteoglycans; PA1 a formation of cross-linked bindings in bio-polymers; PA1 anomalies in the immunological responses; PA1 a cellular fall; PA1 a cell and tissue disorganization; PA1 keratosis; PA1 insufficient recovery processes.
In view of all these negative effects exerted on the skin by the sunlight and, more specifically, by UV rays, this phenomenon cannot be ignored and it would not be possible to permit a devastation of the skin in favor of a striking and agreeable, temporary and transient tanning.
It is necessary to intervene before an irreversible end disaster and before a cutaneous ruin and to protect and cure the skin with attention, prudence, accuracy and, in other words, with intelligence.
This can be obtained by an accurate and exact use of preventive products.
At present the use of solar filters is greatly used by people exposing themselves for long time periods to the sunlight.
The use of solar filter containing creams and milks is suggested by an actual observation that the UV ray impact will cause on skins not naturally or artificially protected, an aggression with damage of various results (free radicals, peroxidation, erythemas, inflammation and so on).
This will cause the skin to prematurely age and, accordingly, on the face, the formation of the wrinkles which represent a visible minifestation of this UV damage.
At present it is necessary to prevent the violent UV (both UVA and UVB) impact from occurring, by using solar filters preventing the damaging radiation, in a different degree depending on the concentration, from penetrating through the skin with the consequent damage.
The commercially available solar filters are constituted by chemical synthetic substances, in general not physiological and not natural substances, which present the property of absorbing the UV rays thereby neutralizing their deleterious activity; however, they also have the consequent feature of hindering the tanning which, on the contrary, represents the continuously searched desire of a person exposing to the sun.
Anyhow, the most serious problem related to the use of conventional solar filters is the continuously increasing diffusion of cutaneous intolerances and reactions, due to the nature and concentration of these substances which will cause undesired side manifestations which, in some cases, discourage the use of said solar filters.